Electric horn



D. -A. M CONNELL ELECTRIC HORN Fil'ed May a. 1922 mommy Patented July 1928.

UNITED srArEs PATENT OFFlCE.

DUNCAN A. MCOONNELL, 0F MONTCLAIR, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGN- MENTS TO DELCO-REMY CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

ELECTRIC HORN.

Application filed May '3 1922, Serial No. 558,109.

This invention relates more particularly cuit is closed and in the other direction by an elastic element which may be the diaphragm either alone or in combination-with auxiliary springs.

The general purpose has been to embody the above essentials'in a compact, simple structure having few parts, cheap to make and assemble. yet durable, easily adjustable and efliciently functioning, both electrically and acoustically. The special features in- -lll clude the following,

The rear casing of the horn is a drawn metal shell shaped to afford the structural frame andvsupport for the solenoid. Preferably also there is a seat for a supplemental recoil spring and a seat for the diaphragm, embodied in the same single piece shell, insuring proper spacing and relative arrangement for all the above-mentioned parts.

The drawn metal shell which affords the support for the solenoid coil elements is of mild steel arranged to afiord the external magnetic circuit for the solenoid. There are special end discs'of magnetic material, one encircling the exteriorly displaced end of the solenoid coreand the other closely confronting the other end of the corethe end toward which the core is to be sucked by the solenoid. Thus the gaps in the magnetic circuit at'the respective ends of the core are a minimum and the motor efliciency of the coil is correspondingly increased.

The power stroke of the solenoid core 15 in a direction-to push the diaphragm outward and the supplemental spring for checking the rearward movement of the plunger,

and the contact spring for making and breaking the circuit, are both located between the solenoid and the diaphragm.

The contact spring-is between the recoil spring and the diaphragm and preferably has its fixed endsecured by the same clamping means employed to secure the recoil spring. The co-operating stationary contact is on a screw rod extending through the rear of the casing and the contacts function.

through an opening formed in the recoil spring.

The recoil spring is preferably rigidly clamped at one end only, the other end extending loosely into a slot beneath a head which closely limits its spring movement but doesnotinterfere with en'dwise and angular movements of the spring when it is bowing in normal operation of the device. The recoil spring is not secured to the plunger, but loosely surrounds the plunger stem so as not to interfere with the automatic self-centering and self-aligning tendency of the core as it reciprocates in the solenoid and it engages the plunger head only against a rearwardly directed surface thereof. The latter feature has the advantage that the plunger head and recoil spring are free to function independently from the time the recoil spring reaches its midway or untensed position on the forward 'stroke'until the same position is passed on the rear stroke of the plunger.

As the recoil spring is'not positively actuated on the forward stroke by the plunger, a separate contact spring is provided which is so actuated. Its free end extends in the path of a forwardly presented surface of the plunger head-so as to be positively actuated thereby on the outward or power stroke but not attached. Hence the head and contact spring are free to function independently from the time said spring reaches the contact closing position on the rearward stroke until the plunger reengages it on the forward stroke. A

Thus the head is unattached either to the diaphragm or to the buffer spring'orto the contact spring, although the size and spacing of these elements are'preferably such that .they are in contact when in normal-rest position. v

The above and other features of.- my in: vention will be more fully evident from the following descriptionin connection withthe accompanying drawings, in which Fig. 1 is a vertical longitudinal section of the device.

Fig. 2 is a transverse section-on the line 2-2, Fig. 1.

Fig. 3 is a view like Fig. 1 but showing .a part of the device on a larger scale.

The projector 1 ma be of sheet-metal of any known or desire construction, brazed or otherwise secured toa stamped metal iii) member 2 forming the front closure and.

clamp for the diaphragm 3.

The rear casing is formed with the, cooperating diaphragm seat 4 against which the diaphragm is clamped. preferably by spinning inward the metal of front casing as at 5.

The rear casing also comprises a cylindrical or body portion 6. the rear wall 7, the rearward cylindrical boss 8, the annular seat 9 of slightly greater diameter than 6,

and a second annular seat 10 of greater dia-- V I through which the threaded portion 32 of meter than 9.

The solenoid contained within the casing comprises a winding 11 which may consist of wire having a flexible enamel insulating coating, wound on'a tubular member or sleeve 12 of insulating material which is preferably thin and hard and. having a smooth inner surface adapted to withstand the'wear and afford minimum friction for.

the reciprocating core 13. The end washers 14 are of similar insulating material.

The structural support for the rear end of the coil is afforded by a flat annular member 15 of iron having the insulating sleeve fitted therein and supported thereby. This member 15 directly engages the shell to afford low resistance magnetic circuit therethrough. Preferably it is-large enough to fit the interior ofthe cylinder 6, so as to be accurately centered thereby.

The forward support for the solenoid coil is an iron disc 16 which fits laterally against the shoulder 9 and peripherally against the cylindrical annulus .17 of the casing.

The disc 16 has a central'boss 18 having an outer shoulder 19 fitting within the insulating sleeve 12, a rear surface 20 closely confronting the forward surface of core 13 and formed with a central opening 21 large enough to permit free passage of the plunger shank 22 which is rigidly secured to and projects from the center of core 13.

It will be evident that in manufacture the above-described elements 11, 12, 14, 15 may be secured together before assemblin them, but the disc 15 may be merely slippe on 12,

then. inserted in cylinder 6 and thereafter disc 16 inserted with its periphery engaging 17 and its boss projecting within 12. Being already accurately centered, disc 16 may be secured from withdrawal in any de sired way, as for instance, by slightly deforming and punching outward the metal of the disc or punchin inward the metal of the shell, as 'at 23, ig. 2.

In the particular arrangement shown, the screw rod 24 may be utilized as means for clamping disc 16 against the parts intervening between it and the rear face of the shell.

The primary function of' the rod '24, however. is that of adjustable support for the stationary contactmember 25. Pursuant to three of these elements. J At the for-ward end it is screw threaded to a sleeve 26 which 'may be the barrel of a brass rivet having a head 27 held in position by riveting over the other end of the barrel as at 28 upon a washer 29. Between the disc-16. {and the rivetis the-insulating sleeve'30. At ithe rear end there is a single insulating sleeve 31 rod 24 extends freely without screw threaded engagement therewith. The rod may be screw adjusted to project any desired distance from the disc 16 and when so adjusted a clamping nut 33 may b'e'screwed down to lock said rod 24 in the adjusted position.

The recoil spring 34 spans the recessin front of disc 16. being supported on an annular face 10 of the casing. One end of 34 is clamped as by rivets 35. 35, in intimate engagement with the flat surface of '10. The other end extends under an overhanging lug 36 but is not clamped thereby, and hence this end is free for angular and endwise play when spring 34 bows in normal operation of the device.

As described above, the recoil spring 34 preferably loosely surrounds the plunger stem 22 and engages the plunger only against rearwardlyi directed surface 38 on the plunger. This surface is on a collar 39. which is preferably a part, of or secured to said stem 22. For convenience in applying the spring 34 to the stem. said spring is provided with a circular opening 40-which.

is slightly larger than the maximunr diameter of 39, from which circular opening eX- tends a slot 41 of slightly greater diameter than the stem 22 and of a length slightly greater than the distance tothe-far side of the stem. 1 j

The circular opening 40 is preferably located opposite the fixed contact 25 in operative relation. to the movable contact 37 on contact spring 37. This contact spring 37 is secured against the forward face of recoil spring \34 and preferably by means of the same rivets 35 which hold said recoil spring in place. The said spring 37 maybe initially formed with a forward curvature or set which is flattened out when rivets are headed down. Spring 37 is bent outwardly to form an offset portion 37", the end of "which engages groove 42 adjacent the for- 3 the plunger makes its reciprocation rear wardly of'the normal or midway position. The device is actuated by electric current supplied from any suitable source, as for instance, direct current from the storage .battery of the lighting and starting system of an automobile. As shown, the circuit is serially through a suitable exterior binding post 44, wire 45, coil 11, wire 46, projection 29 on washer 29 and through the fixed contact to the movable contact 37. Thence the return may be by another wire or by a ground as through the horn casing and the frame of an'automobile. a

In operation, the glosing-of the circuit energizes thesolehoid which sucks forward the core 13, bowing the diaphragm3 outwardly and also flexing spring 37 and breaking the circuit at 37. The solenoid being de-energized the resiliency of the outwardly bowed diaphragm forces the rearward return stroke of the core 13. During the rearward stroke, the spring37 is stopped by fixed contact 25, and the rear surface 38,

, ciprocation of plunger 13. Such increase in amplitude does not afiect contact spring 37 which has no 'movement'rearwardly of the midway position. When the stiffness of the spring elements is properly designed with reference to weight of core 13 and the time ment' of the note produced by the horn.

period of the coil ll', the synchronized,

armonious action of the coil 11, diaphragm.

3, recoil spring 34 and contact spring 37 may be plerfected merely by trial adjustt e fixed contact rod 25, preferably during operation of the device, the-proper adjustment and harmony of operation being determined by the loudness and quality of As an illustration of suitable proportions, we may instance a horn having a 3 inch diaphragm, of spring steel about .018" inch in thickness, made as fiat as possible.-

--The buffer spring and contact spring were made of the same spring steel and of the same thickness and of the proportions shown, but it'will be obvious that the above dimensions, as well as the proportions, may be widely varied.

The core of the plunger is, of course, of first quality magnetic iron or steel, but the plunger stem 22 is preferably of non-magnetic material such as 'brass so that it has no tendency to become part of the magnetic circuit when thecore is magnetized. Hence it does not attract or-stick to any of the adjacent members. Bronze or brass also seem to have an acoustic advantage'over steel or iron, because it is softer and seems to have less elastic recoil. Hence it is less likely 'to cause chattering contact with the springs and with the diaphragm. While the stem 22 may be screw threaded into the core 13, a

drive fit will be cheaper and'equally satis factory, especially where the stem is of brass.

It is to be noted that the thin spring steel strip-34, being clamped at oneend only, opposes rearward movement only by its trans verse stifl'ness. No matter how far it bows rearwardly, the free end yields and the longitudinal elasticity (stretchability) of the strip is never brought into play. Hence the strip functions as an auxiliary recoil device assisting the suction of the solenoid coil in I stopping the rearward I movement. Withv this relatively uniform resilience applied throughout the rearward half of the plunger reciprocation, the distance and speed of said rearward half of the movement, and thereby the frequency of the plunger strokes, may be adjusted within reasonable limits by varyingthe time of closure of the circuit and thus the time of establishing forward suction in the solenoid coil- This may be lit).

accomplished by slight adjustment of the stationary contact 25 as above described. This functioning is noticeably different from that which results where the plunger is secured to a transverse bar or strip which is clamped at both ends. In such case the bar is very stiff relative to the weight of the plunger and the two vibrate at a rate which is practically predetermined bythe stiffness of the bar.

I claim: 4

1. A signalling device comprising, in cembination, a casing supporting achorn; a diaphragm; magnetic discs provided in said casing forming partitions therein; a rod screw-threaded at both ends, one of which is in threaded connection with an insulated collar on the one disc while the other end of the rod is slidably carried in an insulating collar supported in the other disc; va .lockv nut on the end of the rod that is slidably 'carried;.a contact element on the other end ofthe rod; a movable contact arm adapted to engage said contact element; and.elec tro-magnetic means carried by the discs and including an armature having means for disengaging said contacts and striking the diaphragm.

2. A signalling device comprising, in combination, a casing supporting a horn; a diaphragm; discs provided in said casing forming artitions therein a contact carrying mem er insulatingly supported by said discs; means for adjusting said contact carrying member relative to sald dlscs; a

movable contact member supported by the casing so as to engage the stationary contact; and a solenoid coilsupported between said discs and containing a plunger-core adapted to be actuated by said coil said plunger core including means adapted to strike the movable contact member and diaphragm.

, ,3. A signalling device comprising, in combination, a cup-shaped casing formed of thin magnetic material; a horn supported on the edge of said casing; a diaphragm interposed between the horn and casing; discs of comparatively thicker magnetic material than the casing held in spaced relation within said casing and forming partitions therein; a stationary contact; means insulatingly supporting said contact on said discs; a movable contact member supported by the easing so as to permit said member to engage with the stationary contact; a solenoid coil supported between said discs, and insulated therefrom, said coil containing a plungercore; and a member on said plunger core adapted to strike the movable contact and" diaphragm.

4. A horn of the type comprising an elastic diaphragm, a plunger for vibrating the diaphragm, a solenoid coil actuating a plunger core and a circuit breaker operated by movements of said plunger, and, in combination with said-parts, a rear casing element comprising a drawn metal cup of mild steel formed with a cylindrical-body portion, a forward seat for the diaphragm,,an intermediate seat of less diameter for a supplemental recoil spring, anda seat-of still less diameter for a transverse partition member, all parallel, spaced-apart and embodied in the same single-piece shell.

5. A signalling device, comprising in combination, a casing; a diaphragm carried by said casing; an electromagnet in said casing, having a movable armature provided with a head ortion; a circuit controlling device for said electromagnet, comprising a resilient member supporting a contact, said memher being secured at one end, to the casing, the free end thereof engaging the head portion of the armature; a stationary contact adapted to be engaged by the contact on the said casing; an electromagnet 1n said casing,-

resilient member; andv an apertured recoil spring attached at its ends to the casing and located in a plane between thesaid resilient member and'the stationary contact, and engaging the armature head portion, the contact on the resilient member extending through the aperture in the recoil spring.

6. A'signalling device, comprising in combination, a casing; a diaphragm carried by having a movable armature provided witha head portion located between the magnet and the diaphragm; a circuit controlling device for said electromagnet, comprising a resilient member supporting a contact, said member being secured at one end, to the casing, the free end thereof engaging the head portion of the armature on the side thereof adjacent the diaphragm; a stationary 1 contact adapted to be engaged by the contact on the resilient member; and an apertured flange and shoulder portions transverse .to

,the axis thereof; a diaphragm secured to the flange portion; a flat recoil spring havingone end secured to the shoulder portion, the other end being slidably supported thereon;

a solenoid magnet havinga plunger I core provided with a head portion, one side of Whichis engaged by the recoil spring; a circuit interrupter for the said magnet, comprising a flexible contact member one end of which engagesthe other side of thearmature head portion, the other end of said flexible contact member being secured to the casing shoulder; and common" means for securing the recoil spring and flexible contact member to the shoulder of the casing. v

8. A signalling device, comprising in combination, a drawn metal, cup-shaped casing having a flange and a shoulderportion; a diaphragm secured to said flange portion; an apertured partition member in said casing; a solenoid coil supported by said partition member; a plunger core in said coil; an apertured blade spring spanned between opposite portions of the casing shoulder, one end being secured to the shoulder, the other being slidably supported thereon; a stem secured to the plunger core and extending loosely through the, partition member and blade spring, said stem having a head, portion at its end adapted to strike the dia-' and State of New Jersey this 10th day of April, A. D. 1922.

DUNCAN A. 'MG'CONNELL. 

